“Endarterectomy” refers to a removal of material from an inside surface of the one or more arteries; the material on the inside surface is known as “plaque” and is often mechanically of a sticky flexible nature. An example of an endarterectomy procedure is Carotid endarterectomy (CEA), which is a surgical procedure employed to reduce a risk of stroke by at least partially correcting for stenosis, namely narrowing, in one or more common carotid arteries of the human body.
A natural process known as Atherosclerosis which occurs in the human body causes layers of plaque to form in the one or more arteries. In the carotid arteries atherosclerosis usually occurs in a fork where a common carotid artery divides into a corresponding internal carotid artery and a corresponding external carotid artery. The layers of plaque have a tendency to build up in the inner surfaces of the arteries, namely lumen, and cause narrowing and associated constriction of the arteries, thereby rendering blood supply to the human brain at least partially restricted. Pieces of the plaque, known as emboli, are susceptible to break off, namely become embolized, and travel up the internal carotid artery to brain regions, whereat the pieces risk blocking blood circulation, and thereby risk causing death of brain tissue which requires to be constantly furnished with oxygen and nutrients to survive.
In practice, it is found that the layers of plaque cause symptoms which are noticeable by patients themselves. The symptoms are often experienced as temporary or transitory strokes, namely transient ischemic attacks (TIA's). For purposes of conventional temporary diagnosis, TIA's last less than 24 hours; after 24 hours, TIA's are known as strokes.
In situations where the plaque does not manifest as noticeable symptoms, patients are still at a higher risk of stroke in comparison to a general human population, but not as high a risk for patients with symptomatic stenosis. An incident of stroke, including fatal stroke, is in a range of 1% to 2% per year. Surgical mortality as a result of executing endarterectomy lies often in a range of 1% to 2% of patients, but is susceptible to lying in a larger range of 1% to 10% in certain circumstances. Thus, execution of endarterectomy potentially provides potential benefits but also introduces additional risk.
In carotid endarterectomy, a surgeon opens a human carotid artery of a patient to be treated and mechanically removes plaque, namely a sticky fat-like material from the artery. A newer procedure, known as endovascular angioplasty, threads a catheter up from a groin region of the patient, around an aortic arch, and up a carotid artery to be de-plagued. The catheter employs a balloon-type structure to expand the artery, thereby providing an opportunity for a stent to be fitted to hold the artery open if required. In a plurality of clinical trials, a 30-day post-operative risk of heart attack, stroke, or even death was significantly higher when stenting was employed in comparison to just endarterectomy, namely 9.6% for stenting versus 3.9% for endarterectomy. The European International Carotid Stenting Study (ICSS) found that stents had almost double a rate of complications occurring in comparison to just endarterectomy.
When performing endarterectomy on patients, it is desirable to try to reduce a risk of post-operative complications, for example post-operative complications which can result in strokes, or worst case death, and also short- and longterm progression of atherosclerosis. Contemporary risk prediction methods for use in selecting appropriate post-operative treatments for endarterectomy patients involves assessing parameters indicative of:                (a) age of patient, E;        (b) smoking habits of patient, S;        (c) serum cholesterol concentration of patient, C;        (d) diabetes status of patient, D; and        (e) blood pressure of patient, P.        
The risk prediction determines a degree of aftercare required, for example prescribed certain types of medication, or subjected to additional invasive treatments; the risk R and a suitable treatment strategy T are defined by Equations 1 and 2 (Eq. 1, Eq. 2):R=F1(E,S,C,D,P)  Eq. 1T=F2(E,S,C,D,P)  Eq. 2wherein F1 and F2 are multi-parameter functions.
A problem arising in practice is that Equations 1 and 2 (Eq. 1 & Eq. 2) are not sufficiently accurate, such that individuals susceptible to short-term and long term major cerebrovascular and cardiovascular ischemic events are not identified accurately. A more accurate risk prediction is desirable which will aid medical staff to treat high-risk patients more aggressively than others.